User devices (sometimes referred to as user equipment, or UE), such as cellular telephones, may connect to a variety of wireless telecommunications networks that are operated by different companies. These telecommunications networks may be cellular networks that operate according to a variety of protocols, such as a Long-Term Evolution (LTE), a Voice Over LTE (VoLTE), a LTE in unlicensed spectrum (LTE-u), or a fifth generation mobile network (5G) protocol. In the course of a user device registering to, and communicating via, a telecommunications network, information that identifies a user of the user device may be conveyed between the user device and the telecommunications network.